Friday, September 21, 2007

'Hobbit' Was Distinct Species, Wrist Bones Indicate

An analysis of the wrist bones of the tiny prehistoric human dubbed the "Hobbit" bolsters the theory that it was a new species of human and not some aberration of modern man, a study released Thursday said.

Scientists who examined the fossilized remains of the pint-sized human using three dimensional laser imaging say the anatomy of its wrist is primitive -- more akin to that of contemporary apes or ancient human ancestors than modern man or his immediate predecessors.

The creature's wrist lacks a modern innovation seen in homo sapiens and Neanderthals, a wrist that distributes forces away from the base of the thumb and across the wrist for better shock-absorbing abilities.

That suggests that the "Hobbit," whose remains were found on a remote Indonesian island in 2004, evolved at an earlier point in the history of mankind than either modern man or Neanderthals, the authors of the paper said.

"The wrist doesn't show the same specialization for tool behaviour as modern man or Neanderthals," said Matthew Tocheri, a paleoanthropologist at the Smithsonian Institute in Washington.

"It retains the same primitive morphology as ancient hominids."

Tocheri contends these latest findings should settle once and for all the heated debate over whether the creature constitutes an entirely new human species, or whether as some critics contend, it's a pygmy or a modern human afflicted with microcephaly, a virus that stunts the growth of the brain.

"This seals the deal," said Tocheri. "Modern humans do not show up with a chimpanzee hand."

The ancient remains have stirred controversy ever since a team of Australian and Indonesian anthropologists announced their discovery in 2004.

The team that found the remains of the 1m (3ft) 18,000 year-old female on the Indonesian island of Flores claimed it was a member of a heretofore unknown species, formal name Homo floresiensis.

They speculated that it was descended from Homo Erectus or some other ancient species that reached Flores just under a million years ago and that, cut off from the rest of the world, the species evolved a small stature and a chimp-sized skull.

The notion that a human "cousin" that lived on a remote island populated by pygmy elephants and komodo dragons, and whose existence overlapped for a period with that of modern humans, caused a sensation, but some critics questioned whether the ancient bones belonged to a pygmy or a microcephalic -- a human with an abnormally small skull.

In 2005, the team that made the discovery got a boost when researchers at Florida State University who did some 3-D computer modeling of the "Hobbit's" brain case concluded that it was not a human born with microcephalia, but a new species closely related to Homo Sapiens with a highly evolved brain.

Later that year, the team that made the initial discovery announced that they had recovered bones from a total of nine individuals from the Liang Bua cave where the "Hobbit" was originally found, further shoring up their assertions.

In his paper published in the journal Science, Tocheri suggests that his work supports the theory that the miniature prehistoric species found on Flores is descended from a hominid ancestor that migrated out of Africa up to 1.8 million years ago, before the evolution of the anatomically modern wrist seen in Neanderthals and contemporary humans.